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Exploiting particle shape and connectivity to interrogate flocculated suspension mechanics.

English title Exploiting particle shape and connectivity to interrogate flocculated suspension mechanics.
Applicant Vermant Jan
Number 157147
Funding scheme Project funding (Div. I-III)
Research institution Departement Materialwissenschaft ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Material Sciences
Start/End 01.12.2014 - 30.04.2018
Approved amount 301'939.00
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All Disciplines (2)

Discipline
Material Sciences
Chemical Engineering

Keywords (3)

soft matter; rheology; colloidal materials

Lay Summary (French)

Lead
Ameliorer les propriétés des gels en utilisant des variations de forme des particules elementaire.
Lay summary

Ce projet vise à fournir une meilleure compréhension sur comment les propriétés de gels peuvent être contrôlés. Les gels sont une classe de des « matériaux molles » que l'on rencontre dans une large gamme d’applications. Exemples des gels on trouve dans des produits alimentaires, des produits de soin personnel, ainsi que des matériaux de construction ou des formulations pharmaceutiques. Indispensable au bon fonctionnement de ces matériaux sont les façons, parfois inhabituelles, dans lesquelles ces matériaux coulent. Dans le projet, nous essayons de fournir une meilleure compréhension de la façon dont les propriétés des matériaux, et en particulier les propriétés d'écoulement, peuvent être améliorées. Bâtir des gels forts, ou conférer la même propriété mécanique avec une quantité bien inférieure de particules,  sont des objectifs qu’on espère atteindre. Nous profitons de nouvelles possibilités de faire des particules avec des géométries différentes, avec des formes, tailles  et interactions contrôlées. Nous comptons également sur ??des nouvelles techniques et instruments microscopiques pour étudier la dépendance de la structure sur les déformations des gels en fonction de leurs propriétés mécaniques.

 

À la fin du projet, nous aurons à notre disposition des méthodes nouveaux et des stratégies pour étudier et améliorer ces matériaux très pertinents, et nous espérons fournir au moins minimalement un ensemble de règles de «conception».

 

Direct link to Lay Summary Last update: 29.10.2014

Responsible applicant and co-applicants

Employees

Publications

Publication
Superposition rheology and anisotropy in rheological properties of sheared colloidal gels
Colombo Gabriele, Kim Sunhyung, Schweizer Thomas, Schroyen Bram, Clasen Christian, Mewis Jan, Vermant Jan (2017), Superposition rheology and anisotropy in rheological properties of sheared colloidal gels, in Journal of Rheology, 61(5), 1035-1048.
Quantifying the dispersion quality of partially aggregated colloidal dispersions by high frequency rheology
Schroyen Bram, Swan James W., Van Puyvelde Peter, Vermant Jan (2017), Quantifying the dispersion quality of partially aggregated colloidal dispersions by high frequency rheology, in Soft Matter, 13(43), 7897-7906.
Simple microfluidic stagnation point flow geometries
Dockx Greet, Verwijlen TOm, Samples Wouter, Nagel Mathias, Moldenaers Paula, Hofkens Johan, Vermant Jan (2016), Simple microfluidic stagnation point flow geometries, in Biomicrofluidics, 10(4), 043506.
Convective Cage Release in Model Colloidal Glasses.
Jacob Alan R, Poulos Andreas S, Kim Sunhyung, Vermant Jan, Petekidis George (2015), Convective Cage Release in Model Colloidal Glasses., in Physical review letters, 115(21), 218301-218301.

Collaboration

Group / person Country
Types of collaboration
Princeton University United States of America (North America)
- Publication
SMART, Dept of Chemical Eng. KU Leuven Belgium (Europe)
- Publication
- Research Infrastructure
FORTH Greece (Europe)
- Publication
- Exchange of personnel
MIT United States of America (North America)
- Publication
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
90th ACS colloids& surface science symposium Poster Influence of particle anisotropy on cluster rigidity and rheology of colloidal gels 05.06.2018 harvard, United States of America Colombo Gabriele Alessandro;
18th annual european rheology conference Talk given at a conference Role of polymer matrix architecture on the rheology and flow induced microstructure of colloidal dispersions 17.04.2018 sorrento, Italy Vermant Jan; Colombo Gabriele Alessandro;
89th Society of Rheology meeting Talk given at a conference Superposition rheology and anisotropy in rheological properties of sheared colloidal gels 09.10.2017 Denver, United States of America Colombo Gabriele Alessandro;
CECAM workshop Talk given at a conference Superposition Rheology and Anisotropy in Rheological Propertiesof Sheared Colloidal Gels 21.06.2017 Lyon, France Vermant Jan;
17th annual european conference on rheology Talk given at a conference nfluence of particle shape on cluster rigidity and rheology of colloidal gels 05.04.2017 copenhagen, Denmark Colombo Gabriele Alessandro;
Nanoparticles with Morphological and Functional Anisotropy: Faraday Discussion Talk given at a conference From near hard spheres to colloidal surfboards 04.07.2016 Glasgow, Great Britain and Northern Ireland Vermant Jan; Palangetic Ljiljana;
20th Anniversary Meeting of the European Society of Rheology, Zürich, Switzerland date:1 April 2016 Poster Anisotropy in the Rheological Properties of Sheared Colloidal Gels 01.04.2016 Zurich, Switzerland Colombo Gabriele Alessandro; Vermant Jan;


Communication with the public

Communication Title Media Place Year
Other activities demonstration setup of colloidal aggregations German-speaking Switzerland 2018

Awards

Title Year
Onsager professorship and MEdal, NTNU. https://www.ntnu.edu/onsager/professorship 2016

Associated projects

Number Title Start Funding scheme
163501 Directed self-assembly of non-spherical colloids 01.02.2016 International short research visits
192336 Rheology and 4D imaging of designer colloidal gels and their applications 01.04.2020 Project funding (Div. I-III)

Abstract

The goal of this project is to make a significant step in the understanding of the flow behaviour of colloidal gels. These soft materials exhibit a number of technologically important properties, such as a yielding (solid-liquid transition) and a complex time dependent behavior of the viscosity called thixotropy. Whereas these features have been extensively documented in literature, the prediction of the elastic properties from the fundamental properties of the suspension (concentration, shape, interaction potential, flow history) remains challenging, and different theoretical approaches diverge and do not predict gel properties adequately. Similarly, thixotropy has so far escaped a micromechanical description. Recently, it has been suggested that the elastic modulus of a suspension can be simply related to the volume fraction and the rigidity of elastic clusters, even when they do not percolate. It has been suggested that the volume fraction of load bearing structures provides a conceptual framework to quantitatively connect the flow-induced microstructure of soft materials to their nonlinear rheology, possibly even their thixotropic response. So far, an array of scattering techniques has been used on a wide range of colloidal gels composed of spherical particles, and whereas the microstructure has been shown to change over many length scales and being spatially very anisotropic, no direct link between the observations and the different concepts has been presented. One of the main reasons seem to be that yielding phenomena and the changes in microstructure are highly localized, as shown in recent experiments in our group in 2D. These may not be adequately detected or described in scattering experiments, which average over the entire volume. In the present work, we will use both novel techniques and suitable model systems that can be directly used to assess critically recent ideas and concepts. On the experimental side we will turn to advanced ultra high speed confocal techniques (> 1000 images per second) developed in our group, which should enable us to identify the mechanisms and phenomena time and spatially resolved in 3D, especially around the yielding transition. Second we will use model systems with non-spherical building blocks. Changing the particle shape (towards both prolate and oblate) while maintaining the same strength of interaction potential, allows us to evaluate the local strength of the elastic clusters by control of the coordination number, which depends on the aspect ratio of the particles. Using even finer control, we can make the particles directionally interacting, which should offer superb control over the local cluster structure. We will tailor the gel microstructure by using particle shape, flow and sample preparation history and varying the type of interaction (depletion, electrostatic, sticky interaction). A particular question, which we intend to answer, is how local particle connectivity controls the mechanical response.
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